Summary With the recent advances in high-throughput biotechnologies and associated flooding of Big Data, there is an urgent demand and shortage of the next-generation PhD-level scientists who have strong biostatistical and computational skills to handle Big Data while understanding biology, especially genetics and genomics. However, traditional training in biostatistics, which emphasizes almost exclusively on statistical theory and methods, no longer meets the need; similarly, to meet Big Data challenge, traditional training in genetics could be expanded and strengthened with more training in biostatistics/data science. As a response, this application continues the development and refinement of an innovative and interdisciplinary pre-doctoral T32 ?Biostatistics in Genetics and Genomics? (BiG2) training program. The primary mission of this training grant is to prepare Biostatistics, Genetics and other predoctoral trainees for leadership roles in biomedical research through excellent training and mentorship in both biostatistics and genetics/genomics. To meet the overarching objective specified by the NIGMS's RFA, our training program requires completion by each trainee of required and elective coursework in an affiliated PhD program with extra training in Biostatistics and/or Genetics, mentored learning through interdisciplinary research projects through lab rotations, development of critical thinking, communication and networking skills, attendance at and participation in journal clubs, seminars and national meetings, successful completion of a program of interdisciplinary research through their dissertation, and future career development, all of which give our trainees broad training in a rapidly expanding field. The most distinctive feature of the proposed training program is its interdisciplinary nature integrating both a biostatistical (or methodological/computational) aspect and a genetic/biomedical aspect. A key is to ensure each trainee learns how to carry out critical, reproducible, cohesive and interdisciplinary research program, including collaborating with various biomedical researchers. We request support for 4-5-6-6-6 slots in years 1-5 for predoctoral trainees from Biostatistics, Genetics and other affiliated PhD programs. Each trainee is to be funded for two years at the early stage of his/her PhD study, after which his/her support will switch to projects funded by the faculty mentors' research grants. As measurable outcomes, in a short term, we will examine the success rates of the trainee's timely completion of their PhD studies and their job placements; in a long term, it will be determined by the success and impact of their future careers in biomedical research; in between, it will be their publications, awards and career transitions around the beginning of their careers.